1. Field of the Invention
This invention relates generally to a ring interface for testing integrated circuits and, more specifically, to a double ended spring probe ring interface for multiple pin test heads, such as 120 pin sentry style test heads.
2. Description of the Prior Art
To interface electrically from a load board to a device under test (DUT) board on multiple pin test heads, there are two rings of etch pads where electrical connections must be made. Currently, the electrical connection is made through a ring interface having a plurality of spring probes, sometimes referred to as pogo pins. Pogo pins are well known in the art. Pogo pins typically have a shaft with a compression portion located at both ends of the shaft. When the ring interface is placed between the load board and the DUT board, the pogo pins are compressed and provide electrical continuity between the two boards.
A major problem with current ring interface is that the pogo pins are coupled to the ring interface by "screwing" the pogo pins into the ring interface. After normal usage of the ring interface, the pogo pins would unscrew themselves from the ring interface. The unscrewing of the pogo pins causes a loss of planarity across the pins (i.e. the top and bottom ends of all of the pogo pins do not lie in spaced-apart horizontal planes) thus causing electrical continuity problems from the load board to the DUT board.
Therefore, a need existed to provide an improved ring interface. The improved ring interface must not lose planarity across the ends of the pogo pins thus causing a loss of electrical continuity from the load board to the DUT board.